A literature review of fungally-derived antitumor agents reveals that the fungi constitute a group of easiliy collected species, indigenous to Western Europe, the eastern U.S. and Japan. Their availability may have been the decisive factor in these drug discoveries. Significantly, their habitat ranges are broad and suggest that other saprophytic and parasitic fungi, worldwide, could have developed distinctive antitumor agents, also. MYCOsearch, through is proprietary fungal isolation techniques and systematic collecting, already has many unique and unusual fungi in its collection. No NCI support is requestd for fungus collecting. We propose to screen representative isolates of at least 100 selected tropical and temperate forest taxa. Broths and agar cultures would be screened against an Adriamycin-resistant tumor cell culture, perhaps L1210, in vitro, using a rapid assay. Parallel antifungal screens would be performed. Dr. J.B. Tunac will be an active consultant to ensure the high quality of the screening effort. All positive cultures would be available to NCI for further screening against human tumor lines. Results may suggest whether additional screening of novel fungi is warranted. Phase II research would involve further primary screening and purification of the antitumor agents from fungi.